Belgian Tim Wellens lived up to expectations when he won the fourth stage of the Giro d'Italia, a 202-km treacherous ride from Catania with a steep finish as Chris Froome struggled.

After three opening days in Israel and a rest day, the Giro finally reached Italian soil, with Wellens tipped as a favourite for the day's stage.

The Lotto-Soudal rider was on the right end of a late split and he sustained his effort on an 800-metre climb up an average gradient of almost 10 percent to the finish line.

He beat Canada's Michael Woods, who was seconds ahead of Italian Enrico Bataglin.

Nicolas Roche was best of the Irish riders on the day, finishing in 33rd, just 21 seconds off the leads. 

Bennett finished among a group of seven riders who were 36 seconds behind the leading group, while Ryan Mullen was much further back, down in 156th, 10:52 off the pace.

Roche is 37th in the overall standings, 1:32 off the lead with Bennett close by in 45th (+1:44). Mullen sits down in 139th (+11:46).

Four-time Tour de France champion Chris Froome, who is under investigation for a failed dope test in last year's Vuelta, struggled in the finale and lost some 20 seconds, according to provisional results.

Australian Rohan Dennis retained the overall leader's pink jersey with a one-second advantage over defending champion Tom Dumoulin of the Netherlands.

Portgual's Jose Goncalves, one of the overall contenders, suffered a couple of mechanical problems in the finale and dropped out of the top 10.